JPH0368922A - Liquid crystal display device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a liquid crystal display device with almost no crosstalk and high brightness.

[Prior art and its problems]

Liquid crystal display devices can be driven at low voltages, have low power consumption, and can be directly driven by ICs, so they have the advantage that they can be easily made smaller and thinner.

In particular, TN type liquid crystals are excellent in terms of low voltage and low power consumption, and have been widely used in wristwatches, calculators, and the like.

In recent years, with the spread of information processing devices such as word processors and personal computers, there has been a demand for portable, thin, and compact devices, and liquid crystal display devices have begun to be adopted as display devices in place of CRTs. In order to display kanji characters in the information processing devices mentioned above, the number of pixels is much larger than that used in wristwatches, calculators, etc., and the driving method for liquid crystal display devices is usually a simple matrix drive in which electrodes intersect in an X-Y pattern. A circuit is used. In the simple matrix driving method, each pixel does not have an independent pixel electrode, so a constant voltage is also applied to adjacent pixels, and the adjacent pixels are not completely hidden, resulting in so-called crosstalk. This may occur.

In order to improve this crosstalk, there is a method of providing a nonlinear element such as a diode, thin film transistor, or varistor for each pixel.

However, it is difficult to arrange diodes, thin film transistors, etc. for each pixel, which number from thousands to hundreds of thousands of pixels, without defects or with almost the same characteristics.There is little variation in characteristics and it can be formed over a large area. It has been desired to create a nonlinear element with

[Object of the present invention]

The present inventors have discovered that a liquid crystal display device that uses a film mainly made of varistor powder as a nonlinear element can provide display with almost no crosstalk. In this case, since the surface portion of the varistor film 44 on the first substrate 41a and the scanning line electrode 45 on the second substrate 41b are close to each other, the first
The current may easily flow from the signal line 43 provided on the second substrate 41a through the varistor film 44 to the scanning line electrode 45 provided on the second substrate 41b, or from the pixel electrode 42 through the varistor film 44. As a result, the voltage between the pixel electrode 42 formed on the first substrate 41a and the scanning line electrode 45 decreases.
A problem arises in that display with desired brightness cannot be obtained. This phenomenon becomes more noticeable as the liquid crystal N46 becomes thinner.

It is an object of the present invention to solve these problems and provide a liquid crystal display device with high brightness and less crosstalk.

[Means for solving problems]

The present invention provides a first substrate having a pixel electrode, a signal line disposed at a distance from the pixel electrode and sending a signal to the pixel electrode, and a varistor connecting the pixel electrode and the signal line; A second electrode is provided facing the second electrode.
In a liquid crystal display device in which a liquid crystal is filled between a substrate and a first substrate and a second substrate, a varistor disposed on the first substrate and an electrode disposed on the second substrate. The present invention relates to a liquid crystal display device characterized in that an insulating means is provided between the present invention and the present invention.

The present invention will be explained below with reference to the drawings.

FIG. 1 is a partially enlarged longitudinal sectional view of a liquid crystal display device in which an insulating means 32 such as an insulating film is provided on the surface of the varistor 12 of the present invention. FIG. 2 is a plan view showing the relationship between the pixel electrode 14, the signal line 13, and the varistor 12 provided on the first substrate 11, and FIG.
3 is a plan view showing the upper scanning line electrode 22. FIG.

On the first substrate ll, a pixel electrode 14 and a signal 1a13 are provided.
The 0 pixel electrode 14 and the signal line 134 are spaced apart from each other, and are electrically coupled by the varistor 12. The interval between the pixel electrode 14 and the signal line 13 is generally 10 to 400 μm. In Figure 1,
An insulating means 32 such as a silicon oxide film is provided on the surface of the varistor film formed on the first substrate. A scanning line electrode 22 is arranged on the second substrate 21 so as to face the pixel electrode 14 . A liquid crystal 31 is sandwiched between the first substrate 11 and the second substrate 21.

As the above-mentioned insulating means, for example, an insulating film may be provided between the side substrates.

The material for forming the insulating film is not particularly limited, and km
Even if it is a chemical substance, it will not stain. As a specific example,
Examples include organic materials such as polyimide, polyamide, polyethylene, dipropylene propylene, polyethylene terephthalate, polyurethane, and polyacrylate, and inorganic materials such as silicon oxide, titanium oxide, aluminum oxide, and glass.

The insulating film can be formed, for example, by dissolving a polymer in a solvent and applying it on the varistor disposed on the first substrate, or
It can be manufactured by coating a portion of an electrode disposed on a substrate facing a varistor. The insulating film is
In addition to the above, it can be formed by various methods depending on the material used, for example (1) by applying molten polymer on the varistor or scanning line, (2) in the case of polyimide, silicon oxide, etc. (3) by baking in the case of low melting point materials such as glass, and (4) by vapor deposition or baking in the case of high melting point materials such as aluminum oxide. It can be formed by a sputtering method. When using a material such as silicon oxide or polyimide which is transparent and has a high insulating effect, it may be applied to the entire surface of the substrate.

In the present invention, if the varistor is a varistor film mainly made of varistor powder, the varistor can be manufactured at any position and size on the substrate. Furthermore, if the varistor film is formed individually between the pixel electrode and the signal line by a printing method using a paste containing varistor powder as the main component, the manufacturing process will be faster than when using thin film formation technology. The method is simple and inexpensive, and it is possible to manufacture elements over a wide area at once, and it is possible to form stable varistor elements with little variation in characteristics.

When the varistor is a varistor film made mainly of varistor powder, by using varistor powder that is approximately spherical in particle size, the varistor dark value voltage between each pixel electrode and the signal line becomes almost constant, resulting in a clear display. . The particle size of barista powder is generally 1 to 300 μm, preferably 2 to 5 μm.
It is 0tIm.

As the liquid crystal used in the present invention, D S (Dynam
ic Scattering) type, T N (Tiii
sted nematic) type, E CD (Elec
trically controlled biref
ringence) type, P C (Phase Chan) type,
ge) type and guest-host type liquid crystals.

〔Example〕

Hereinafter, the present invention will be explained in further detail by showing production examples.

Manufacturing Example 1 As shown in FIG.
Transparent like O! After forming the signal line 13 and the pixel electrode 14 made of mulberry, the varistor element 12 was formed between the signal line 13 and the pixel electrode 14 (gap 20 μm) by a printing method.

Next, a liquid made of an organosilicon compound was applied to the surface of the varistor formed on the first substrate and baked at 500° C. to form a silicon oxide film 32 of about 1 μm on the surface of the varistor.

On the other hand, on a second substrate (glass, PET film, etc.) 21, an electrode 22 made of ITO or the like to serve as a predetermined scanning electrode was formed by patterning.

Next, the substrate of confectionery 1 on which the silicon oxide film 32 was formed and the second substrate were bonded together so as to meet at a predetermined position, and the area around the substrate was sealed with an adhesive leaving a liquid crystal inlet. after that,
Filled with TN type liquid crystal such as Merck ZL11132,
The liquid crystal inlet was sealed with adhesive.

When multiplex driving (duty ratio 1/400) was performed with an AC voltage of ±20 V between the signal line 13 and the scanning line electrode 22 of this liquid crystal display device, the desired pixel area was bright without crosstalk (contrast ratio of 50 or more). ) could be lit.

Production Example 2 A photosensitive polyimide insulating film is coated on the second substrate on which the scanning line electrodes 22 are patterned, and through the steps of exposure using a photomask, development, and baking, a thickness is formed on the part facing the varistor. A 2 μm polyimide insulating film was formed.

Next, the first substrate and the second substrate were bonded together in a predetermined position using the same method as in Production Example 1, and the area around the substrates was sealed with an adhesive leaving the liquid crystal inlet. after that,
Filled with TN type liquid crystal such as Merck ZL11132,
The liquid crystal inlet was sealed with adhesive. When multiplex driving (duty ratio 1/400) was performed with an AC voltage of ±20 V between the signal line 13 and the scanning line electrode 22 of this liquid crystal display device, the desired pixel portion appeared brightly (without crosstalk).
contrast ratio of 50 or higher).

In addition, when explaining, the signal electrode on the second substrate is referred to as scanning line 1.
Although the i-pole is used, the present invention is not necessarily limited to this, and the signal line on the first substrate may be scanned during driving.

〔Effect of the invention〕

According to the present invention, even when the thickness of the liquid crystal layer is reduced, current does not flow from the signal line to the scanning line electrode via the varistor, and a normal matrix circuit between the liquid crystal and the varistor is formed. The brightness allows for high-contrast display.

[Brief explanation of drawings]

FIG. 1 is a partial longitudinal sectional view of a liquid crystal display device of the present invention. FIG. 2 is a plan view showing the arrangement relationship of pixel electrodes, signal lines and varistors on the first substrate, and FIG. 3 is a diagram showing the scanning line electrodes on the second substrate. FIG. 4 is a partial longitudinal sectional view of a conventional liquid crystal display device. 11.21: Board, 12: Varistor, 13: Signal line, 1
4: Pixel electrode, 22: Scanning line electrode, 31: Liquid crystal layer, 32
: Insulation means

Claims (1)

[Claims] (1) A first substrate having a pixel electrode, a signal line disposed at a distance from the pixel electrode and sending a signal to the pixel electrode, and a varistor connecting the pixel electrode and the signal line; In a liquid crystal display device in which a second substrate is provided with electrodes facing each other, and a liquid crystal is filled between the first substrate and the second substrate, a varistor disposed on the first substrate and A liquid crystal display device characterized in that an insulating means is provided between the electrodes disposed on the second substrate.